Serializers – Django REST Framework

The serializers in the REST framework work very similarly to Django’s Form and ModelForm classes. The two major serializers that are most popularly used are ModelSerializer and HyperLinkedModelSerialzer. This article revolves around how to use serializers from scratch in Django REST Framework to advanced serializer fields and arguments. It assumes one is familiar with How to start a project with Django REST Framework.

• Creating and Using Serializers
• ModelSerializer
• HyperLinkedModelSerializer
• Serializer Fields
• Core arguments in serializer fields

Creating and Using Serializers

Serializers are used to convert complex data types, such as Django model instances, into Python data types that can be easily rendered into JSON, XML, or other content types. Serializers also provide deserialization, allowing parsed data to be converted back into complex types after first validating the incoming data. Serializers in Django are a part of the Django REST framework, a powerful and flexible toolkit for building Web APIs.

Creating a basic Serializer

To create a basic serializer one needs to import the serializers class from rest_framework and define fields for a serializer just like creating a form or model in Django. 

Example  

This way one can declare serializer for any particular entity or object based on fields required. Serializers can be used to serialize as well as deserialize the data.

Using Serializer to serialize data

One can now use CommentSerializer to serialize a comment, or list of comments. Again, using the Serializer class looks a lot like using a Form class. Let’s create a Comment class first to create a object of type comment that can be understood by our serializer.  

Now that our object is ready, let’s try serializing this comment object. Run following command, 

Python manage.py shell

Now run the following code  

# import comment serializer
>>> from apis.serializers import CommentSerializer
# import datetime for date and time
>>> from datetime import datetime
# create a object
>>> class Comment(object):
...     def __init__(self, email, content, created=None):
...         self.email = email
...         self.content = content
...         self.created = created or datetime.now()
... 
# create a comment object
>>> comment = Comment(email='leila@example.com', content='foo bar')
# serialize the data
>>> serializer = CommentSerializer(comment)
# print serialized data
>>> serializer.data

Now let’s check output for this, 

To check more on how to create and use a serializer visit – Creating and Using Serializers

ModelSerializer

A ModelSerializer typically refers to a component of the Django REST framework (DRF).The Django REST framework is a popular toolkit for building Web APIs in Django applications. It provides a set of tools and libraries to simplify the process of building APIs, including serializers.

The ModelSerializer class provides a shortcut that lets you automatically create a Serializer class with fields that correspond to the Model fields. 

The ModelSerializer class is the same as a regular Serializer class, except that: 

• It will automatically generate a set of fields for you, based on the model.
• It will automatically generate validators for the serializer, such as unique_together validators.
• It includes simple default implementations of .create() and .update().

Syntax :

Models.py

Just like when building a form or model in Django, the first step in establishing a basic serializer is to import the serializers class from the rest framework and define the serializer’s fields.

Example :

By default, all the model fields on the class will be mapped to a corresponding serializer fields. 
To checkout how to use ModelSerializer in your project, visit – ModelSerializer in serializers – Django REST Framework. 

HyperlinkedModelSerializer

The HyperlinkedModelSerializer class is similar to the ModelSerializer class except that it uses hyperlinks to represent relationships, rather than primary keys. By default the serializer will include a url field instead of a primary key field. The url field will be represented using a HyperlinkedIdentityField serializer field, and any relationships on the model will be represented using a HyperlinkedRelatedField serializer field.

Syntax :

Example :

To checkout how to use HyperLinkedModelSerializer in your project, visit – HyperlinkedModelSerializer in serializers – Django REST Framework.

Serializer Fields

Core arguments in serializer fields

Serializer fields in Django are same as Django Form fields and Django model fields and thus require certain arguments to manipulate the behaviour of those Fields.